Apparatus for exhausting from downhole burner



Sept. 7, 1965 APPARATUS FOR EXHAUSTING FROM DOWNHOLE BURNER Filed Sept. 16, 1963 I IHIIII 2 Sheets-Sheet l INVENTORS CORAL L. DE PR/ESTE'R ANTHONV J. PANTALEO CHARLES W GONVAW Sept 7, 1965 c. l.. DE PRlEsTl-:R ETAL 3,204,696

APPARATUSFOR EXHAUSTING FROM DOWNHOLE BURNER Filed Sept. 16, 1963 2 Sheets-Sheet 2 INVENTORS CORAL DE Pie/ESTER ANTHONY J. PANTALEU CHARLES W. Gom/Aw Quill,

United States Patent C) 3,204,696 APPARATUS FR EXHAUSTING FROM DUWNHOLE BURNER Coral L. De Priester and Anthony J. Pantaleo, Fullerton,

and Charles W. Gonyaw, Walnut Creek, Calif., assignors to California Research Corporation, San Francisco, Calif., a corporation of 'Delaware Filed Sept. 16, 196'3, Ser. No. v308,942 7 Claims. (Cl. 166-59) This invention relates to methods and apparatus for burning a combustible mixture of fuel and air in a well to stimulate production therefrom and more particularly, this invention relates to methods and apparatus for exhausting the gases of combustion from the combustion chamber of a downhole burner and, still more particularly, to removing water from the combustion gases leaving the burner through an exhaust stack.

As known in the petroleum producing art, production from a well can be improved by heating the fluids in the well and in the adjacent producing formation. Heretofore there have been many methods of heating uids in a petroleum-bearing formation penetrated by a well. The most successful of these methods includes burning a combustible gaseous mixture in the combustion chamber of a downhole burner. Examples of downhole fuel and air burners are shown in U.S. Patents 2,887,160 and 2,895,555.

A problem that has prevented the economic use of fuel and air burners in deep wells having a high uid level is the high injection pressure of the fuel and air which is required to exhaust the combustion gases from the combustion chamber into the well. It has heretofore been proposed to reduce the required pressure by connecting an exhaust stack to the combustion chamber to receive the exhaust gases therefrom and to flow the exhaust gases to a level above the iiuid level in the Well or to vent the exhaust gases at the surface. A serious problem, however, has been caused by the water which condenses out of the exhaust gases as the gases cool off while flowing up the exhaust stack. It has been found this water will collect in the exhaust stack. After the burner has been operated for some time, enough water will be collected in the exhaust stack to develop a high hydrostatic head and to thus make the pressure required to force the exhaust gases up the stack prohibitive from an'operational and economic view.

It is therefore a principal object of the present invention to provide a method and apparatus for removing the condensate water from an exhaust stack extending from a downhole burner and to provide for eliminating this water from the exhaust system to thereby allow operation of the burner at a desirable pressure level even in a deep Huid-filled well.

In a broad aspect the present invention includes an elongated exhaust stack adapted to be connected to the combustion chamber of a downhole burner to receive the gases of combustion therefrom. The exhaust stack is extendible from the burner to a desired location above the liquid level in the well. At a predeterminable location in the exhaust stack where condensate is formed condensate removal means are provided to separate the condensate and the exhaust gases. The exhaust gases continue up the stack and are vented. The condensate is collected and removed from the exhaust system.

Additional objects and advantages of this invention will become apparent from the following detailed descripton read in light of the accompanying drawings which are made a part 4of this specification and in which:

FIGURE l is a sectional view of an earth formation penetrated by a well and illustrates apparatus assembled in accordance with this invention;

3,204,696 Patented Sept. 7, 1965 FIGURE 2 is a longitudinal View partially in section and illustrates a preferred embodiment of apparatus assembled in accordance with the invention;

FIGURE 3 is a sectional View taken at line 3 3 of FIGURE 2; v

FIGURE 4 is an enlarged sectional view of a portion of the preferred embodiment of apparatus;

FIGURE 5 is a longitudinal view partially in section and illustrates an alternative arrangement of apparatus assembled in accordance with the invention;

FIGURE 6 is a sectional view taken at line 6-6 of FIGURE 5;

FIGURE 7 is a longitudinal view partially in section and illustrates another alternative arrangement of apparatus assembled in accordance with the invention;

FIGURE 8 is a sectional `View taken at line 8-8 of FIGURE 7;

FIGURE 9 is a longitudinal view and illustrates an alternative embodiment of apparatus assembled in accordancewith the inventioin.

IReferring now to the Idrawings a-nd to FIGURE 1 in particular, the method and apparatus of the invention will be described in greater detail. A better understanding of the invention can be obtained by a brief discussion of a general arrangement of apparatus useful in burning a fuel and air mixture in a well. A downhole burner represented generally by the numeral 20 is located in a well 21 in a desirable position adjacent an oil-producing formation 22. The downhole burner 20 is connected below a standard oil well pump 24 by means of connecting member 25.

A combustible fuel yand air mixture is supplied to the combustion chamber of the burner 20 for combustion therein. For example, a combustible fuel gas and air mixture is supplied to the burner 20 by a means 26 defining a source of gas and means 27 defining a source of air. Appropriate surface piping 28 and 29 connects the respective ga-s and air means Ato a conduit 30 for llow to the burner 20. Suitable valves 31 and 32 are provided on' the surface piping 28 and 29 to control the ow to the downhole conduit 30. Valve means 33 are connected into the downhole conduit 30 to control the flow of the combustible mixture to the burner 20. The combustible mixture is ignited by suitable means such as an electrical ignition means located near the combustion. chamber, and excited by means of the surface electrical system indicated generally 4as 34.

After .combustion has occurred in the combustion chamber section of the downhole burner 20, the exhaust gases are removed from the burner and from the well by means of exhaust stack 35. The exhaust stack 35 is connected to the burner 20 below the combustion chamber and it is vented to the atmosphere through valve 36. This valve 36 is adjustable to control the back pressure on the downhole burner 20. Condensate removal means indicated generally by numeral 37 are located at a predeterminable position in the exhaust stack 35. A drain means 38 is provided for removing the condensate from the exhaust system after the condensate is separated from the exhaust gases in stack 35 and collected by suitable means. Check valve means 39 are connected to the drain means 38 to prevent well liuids from entering the exhaust system.

Referring now to FIGURE 2 and FIGURE 3, the preferred embodiment of apparatus `of the present invention is shown. As heretofore mentioned, a serious problem is caused by the condensate from the exhaust gas collecting in the exhaust stack. The present invention provides means for separating the exhaust gas and the condensate. A collection and drain means collects the separated condensate and removes the condensate from the exhaust system. As the condensate is formed in the exhaust stack it is carried for a short distance upward by the rising exhaust gases. The condensate collects and travels on the inner wall of the exhaust stack 35. Port means such as spiral slots 40 are formed through the wall of the exhaust conduit 35. The slots are cut in a manner to facilitate and promote the removal of water from the inside wall of the exhaust stack 35. The slots 40 are arranged around the wall in a manner such that the upper portion 42 of a slot 40 overlaps the lower portion 41 of its nearest neighbor and so on around the stack 35 for a series of the slots 40. The slots 40 are formed in the stack above the level where condensate begins to form. Thus the condensate carried upward along the wall of the exhaust stack 35 goes through the slots 40 to the outside of the stack 35. The location of the slots 40 is determined by conventional calculations of dew points to find the position in the stack where condensation occurs. The pressure, temperature and volume relationships of a particular downhole burner system are used in the calculations to determine this location.

Condensate collection means 37 are formed around all the port means or slots 40 in exhaust stack 35 to collect the condensate as it cornes through the slots 40. The condensate collection means 37 is for example a tubular member of slightly larger diameter than the exhaust stack 35. The tubular member is arranged concentrically around the stack 35. End plates are connected at the ends of the tubular member to form a seal Ibetween the tubular member and the exhaust stack 35.

Drain means 38 are connected vto the lower portion of the collection means 37. The drain means preferably includes an elongated tubing 38 extending down into the well. The length of the tubing 38 is determined by a number of factors. The tubing 38 must be at least long enough to allow the hydrostatic head formed by condensate in the tubing to overcome the pressure existing at the exit position for the condensate plus some increment of pressure to open a check valve means 39.

Check valve means 39 are connected to the lower end of the tubing 38. The valve only allows flow out of the tubing. It does not permit iiow of uids from the well into the tubing 38. Thus well iluids are prevented from entering the exhaust system. A preferred form of check valve means 39 is shownv in FIGURE 4. The check valve means 39 includes a housing member 43.. A central liow path is provided through the housing member 43 by the holes in baiiie plates 50 and 51. The flow path isnormally closed by piston 44 urged into the hole in the upper bathe plate 51. The piston is opened when the head of the fluid column extending up ow tube 38 is great enough to overcome the pressure in the well plus the incremental pressure of spring 45. Thus as the condensate is formed and collected, a column of water will develop in the drain means 38 and will cause the check valve means 39 to open and allow the condensate to 'be removed from the exhaust system.

An alternative embodiment of apparatus assembled in accordance with the invention is illustrated in FIG- URE 5 and FIGURE 6. An elongated exhaust stack 235 is provided with a short section 236 of reduced diameter. Vertically extending slots 170 are formed in the reduced diameter section 236 to allow condensate to flow through it. A tubular member 171 having substantially the same diameter as the exhaust stack 236 is placed around the exhaust stack and is fixed in a iluidtight manner therewith by end plates 172 and 173. Drain means 238 are connected to the lower portion of the tubular member 171. The drain means are provided with a suitable check valve' means 239 to prevent well fluids from entering the exhaust system. This embodiment of apparatus requires less room in the well and decreases the chances of hang-up in the well.

Refer now to FIGURE 7 and FIGURE 8 where another alternatiV@ @mbodment is illustrated. The gen- Cil eral arrangement of the slots 70 formed in the exhaust stack and the collection means 71, drain means 138 and check valve means 139 are similar to those described heretofore. It is desirable, however, in some circumstances to promote the separation of the exhaust gases and the condensate and to insure that the condensate will be formed and located on the wall of the exhaust conduit 135. A means is therefore provided to direct the condensate against the walls and to agitate the exhaust gas stream to promote deposition of the condensate. A suitable means for accomplishing this result is a suitably formed insert 75 positioned inside of the exhaust stack 135. For example a helically shaped insert 75 insertable in the interior of the exhaust stack and mountable therein is a suitable means to promote condensate contacting the wall of the stack. A flow path is indicated by the numeral 76 is provided between the insert and the exhaust stack for exhaust gas iow up the stack. The exhaust gas however is caused to swirl by the insert and to thus centrifugally promote the separation of the condensate and the gas. The insert is mounted in the stack by suitable means as welding the ends 74 of the insert 75 to the interior wall of the exhaust stack 135.

With reference now to FIGURE 9 an alternate means for disposing of the condensate is shown. In some wells relatively fresh water, such as the condensate would be, can cause severe damage to formations containing watersensitive clays. Thus in these wells it is necessary to prevent -the condensate from contacting the producing formation. When this is necessary, an extension tube is connected to receive all flow coming from the drain tube 138 through the check valve 139. The extension tube 140 directs the condensate into or near the intake 25 of pump 24. The water is taken in by the pump and is thus preventedvfrom contacting the formation.

It is apparent that moditications other than those described herein may be made to the apparatus of this inventionwithout departing from the inventive concept. It is intended that the invention embrace all equivalents within the scope of the appended claims.

We claim:

1. Apparatus for burning a combustible mixture in a well comprising a burner having a combustion chamber, means positioning said burner in a well, means for supplying a combustible mixture to said combustion chamber for combustion therein, an elongated exhaust stack extending up said well and receiving exhaust gases from said combustion chamber, and condensate removal means in said well connected to said exhaust stack for removing condensate from said exhaust stack.

2. Apparatus for burning a combustible mixture in a Well comprising a burner having a combustion chamber, an elongated exhaust stack connected to said combustion chamber and extending up the well, port means forming an opening in a wall of said exhaust stack, a tubular member positionable around said exhaust stack, means connecting said tubular member to said stack adjacent the opening therein to form an annular chamber between said stack and said tubular member, drain means connected to said annular chamber and extending down the well, and check valve means on the lower end of said drain means to prevent well fluids from entering said drain means.

3. Apparatus for burning a combustible mixture in a well comprising a burner having a combustion chamber, an elongated exhaust stack connected to said combustion chamber and receiving exhaust gas therefrom, port means formed in the wall of said stack, a tubular member connected to said stack and forming an annular chamber therewith around the port means, and drain means connected to said tubular member for draining said annular chamber, said drain means including a tubing section extending down said'well.

4. Apparatus of claim 3 further characterized by check 5 valve means on the lower end of said tubing section prevent entry of well iiuids into said tubular member.

5. The apparatus of claim 3 further `characterized by insert means connected in the stack adjacent said port means to promote the separation of condensate and exhaust gas.

6. The apparatus of claim 3 further characterized in that ythe port means are formed in said stack above the level Where condensation occurs in said stack.

7. The `apparatus of claim 3 further characterized in that the port means comprise a series of spirally extending slots formed in the wall of the exhaust stack.

References Cited bythe Examiner UNITED STATES PATENTS Mosher 55-456 Kreager 166-59 Corbett.

Tutton 16659 X Langford 55-456 X Kramer 166-61 Bergson 55-421 X CHARLES E. OCONNELL, Primary Examiner. 

1. APPARATUS FOR BURNING A COMBUSTIBLE MIXTURE IN A WELL COMPRISING A BURNER HAVING A COMBUSTION CHAMBER, MEANS POSITIONING SAID BURNER IN A WELL, MEANS FOR SUPPLYING A COMBUSTIBLE MIXTURE TO SAID COMBUSTION CHAMBER FOR COMBUSTION THEREIN, AN ELONGATED EXHAUST STACK EXTENDING UP SAID WELL AND RECEIVING EXHAUST GASES FROM SAID COMBUSTION CHAMBER, AND CONDENSATE REMOVAL MEANS IN SAID WELL CONNECTED TO SAID EXHAUST STACK FOR REMOVING CONDENSATE FROM SAID EXHAUST STACK. 